Loss and Loss Adjustment Expense Reserves (Loss and LAE Activity) (Narrative) (Detail) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | 12 Months Ended | |
|---|---|---|---|---|
Sep. 30, 2026 |
Sep. 30, 2026 |
Sep. 30, 2025 |
Dec. 31, 2025 |
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| Loss And Loss Adjustment Expense Reserves [Line Items] | ||||
| Weighted average risk-free rates used to discount claim liability | 5.09% | 3.79% | ||
| Lae [Member] | ||||
| Loss And Loss Adjustment Expense Reserves [Line Items] | ||||
| Losses and loss adjustment | $ 2 | $ 7 | $ 3 | |
| Loss and loss adjustment expense reserves | $ 13 | $ 13 | $ 15 | |
| Changes in Loss and LAE Reserves | one-year | |||
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- Definition Changes in Loss and LAE Reserves No definition available.
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- Definition Loss And Loss Adjustment Expense Reserves [Line Items] No definition available.
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- Definition Weighted-average risk-free rate used to discount claim liability for financial guarantee insurance contract. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The amount needed to reflect the estimated ultimate cost of settling claims relating to insured events that have occurred on or before the balance sheet date, whether or not reported to the insurer at that date. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount, after effects of policies assumed or ceded, of expense related to the provision for policy benefits and costs incurred. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Details
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